Tag: importance and classification of angiosperms

Plants growing in bright light are called as sun plants or heliophytes, while plants growing in partial shade or low light intensity are called as shade plants or sciophytes. 

In succulent xerophyte, plants have fleshy organs, where water and mucilage are stored. Depending upon the organ, where succulence occurs, the succulents show chylocauly, i.e., fleshy stem, e.g., Opuntia, Euphorbia, Asparagus; chylophylly ie fleshy leaves, e.g., Agave, Aloe or chylorhizy, i.e., fleshy roots, e.g., Asparagus.

Plants living in dry conditions are called as xerophytes. These plants show many morphological and structural adaptations to survive in dry conditions. In stem the mechanical tissue is well developed and also bark is well developed to retain water

Xerophytes are plants of dry habitats, where the environment favours higher rate of transpiration than the rate of absorption. 

Hydrophytes possess special air storage parenchyma tissue, called as aerenchyma. It makes different parts of hydrophytes, light, spongy and flexible. It makes oxygen produced during photosynthesis, available to roots and other non photosynthetic regions. It can also help in exchange of gases with the atmosphere through stomata present in emerged regions of plants. Xerophytes show structural adaptations to discourage water loss through transpiration and increase water absorption. Such adaptations include thick cuticle, sunken stomata, well developed vascular tissue etc.

Hydrophytes are water loving plants. The hydrophytes with floating leaves have large leaves, stomata and waxy coating on the upper surface. The waxy coating prevent wetting and clogging of stomata.

Pneumatophores are specialized root structures that grow out from the water surface and facilitate the aeration necessary for root respiration in hydrophytic trees such as many mangrove species (e.g., Avicennia germinans and Laguncularia raecemosa), bald cypresses, and cotton (Tupelo) gum (Nyssa aquatica). So, the correct option is "B" (Pneumatophores).

Tropical desert areas are those where there is scarcity of water and extensive heat. Organisms in those areas adapt to survive in that ecological condition. Adaptations like thorns and succulents in flora helps the plants to survive without plenty of water. The leaves and stems undergo modification to conduct photosynthesis in less available water. Animals like frogs, rabbits, snakes, camels, etc. also go through modification in their characteristics to ensure their survival. Large surface of an any organism can lead to radiation of more body heat per unit of mass which can be fatal. Hence, such adaptations is not seen in organisms present in tropical desert.